Shock absorber



[April 1936. J, w. FLYNN 2,038,032

SHOCK ABSORBER Filed Oct. 16, 1955 v 35 opposite direction, suchmovement is initially relower or outer end oi the cylinder M, whichcheck Patented Apr. 21, 1936 Q UNITED STATES PA'lEN'I I OFFICE SHOCKABSORBER John W. Flynn, Waterford, N. Y., asslgnor o! two-fifths toCharles J. Ranney, Troy, N. Y.

Application October is, 1933, Serial No. 693,853 I '1 Claims. (01.ass-s4) The present invention relates to shock ab- ,Figure 1 is acentral. vertical sectional view sorbers. through the shock absorber.

The principal object of the invention is to pro- Figure 2 is a planview. vide a shock absorber which is so constructed that Figure 3 is ahorizontal sectional view taken 'on I the movement of the relativelymovable parts the'line 3-4 of Figure 1, and 5 thereof will beefliciently cushionedthroughout Figure 4 is a sectional view taken onthe line the entire range of such movement. 4-4 of Figure 1.

Shock absorbers of the type used upon automo- The numeral Ill designatesa plunger member biles or other vehicles ordinarily comprise a pisandthe numeral ll indicates a casing member.

ton and cylinder operatively connected to rela- The plunger and casingare relatively movable 10 tively movable parts of the vehicle. Thecylinder with respect to each other and, in use upon an isfnsuallyfilled with a substantially non-'compresautomobile, the plunger isordinarily operatively sible'fluid, such as oil or glycerine, which iscaused connected to the body 01' the automobile or other to mnve throughrestricted ports in the device by vehicle, while the casing isoperatively connected l8 reason 01' the relative movements of the pistonto the axle or running gear. It willbeunderstood, i5 and cylinder. Asubstantially non-compressible however, that the manner of connection ofthese fluid will cushion the movements of the elements two elements tothe relatively movable parts of o! the device under ordinary conditions,but it the vehicle or other mechanism may be reversed, the movement isextremely sudden or severe, the also, that these elements of the shockabsorber 2o fluid may not flow through the restricted ports may beoperatively connected to the respective with sufllcient rapidity and,being non-compresparts of the vehicle or mechanism in any suitablesible, will retard the movements of the relatively manner. movable partsof the device to such an extent that The casing ii is provided witha'cylinder l2 they are,- in effect, locked together, causing the whichmay be termed the primary cylinder of body and running gear of thevehicle to move as the device and in which a piston head I3 in- 25 one,instead of causing the movement of one to be cluded in the plungermember I0 is adapted to recushioned with respect to the other.ciprocate. The cylinder I2 is filled with a sub- The shock absorber ofthe present inven-- stantially non-compressible fluid, such as oil ortion comprises a structure wherein the moveglycerine. The casing II alsohas operatvely asso ment of the parts ofthe device in one (11- sociatedtherewlthasecondary cylinder H, which rection is directly resisted by asubstantially has a piston l5 movable therein. The piston l5non-compressible fluid which, in turn, transis ordinarily held near the.upper or inner end mits the shock of a compressible fluid. Upon oi thesecondary cylinder J4 by means of a coil movement of the parts of thedevice in the spring IS. A check valvefjfl 'l' is provided at the sistedby reason of the fact that the non-comvalve is normally held closed by aspring, as pressible fluid flows through a restricted aperture. shown.Beneath the piston IS, the cylinder ll However, should the movement betoo sudden orcontains air under atmospheric pressure. Should severe, therestricted'aperturewill opentopermit the air in the cylinder l4 escapefrom any cause,

40 the non-compressible fluid to flow more 'readily the check valve l'lwill open to permit air to flow 40 therethrough, thus enabling the partsoi the deinto the cylinder l4, thereby maintaining atmosvlce to continueto move. with respect to each pheric pressure in this cylinder. other incushioning movement instead of being The lower end of the primarycylinder I2 is locked together. suitably connected to the upper end ofthe sec- While the shock absorber oi the present invenondary cylinder H,as by means of a passage ll, 45 tion is particularly designed for useupon vehicles, which passage is normally held closed from the it will beunderstood that it is of general applicylinder l2 bya valve l9 heldseated upon a valve cation. seat 20 by means of a spring 2|. The valveI9 Another object oi the invention is to provide a has seating suriacesupon both faces thereof and so shock absorber or the type described,which is when it is forced downwardly against the action sturdy andcompact in construction and which of the spring 2 l by means of a highpressure withmay be economically manufactured. in the primary cylinderl2 induced by downward Other objects and advantages of the inventionmovement of the plunger Ill, the valve 19 will be will be apparent fromthe following specification seated upon a seat 22 beneath the mouth ofpasand drawing, wherein: sage l8, thereby opening this passage. Itwillbe 55 observed that the valve I9 is of the plunger type of the e l9.

The casing II also includes a reservoir 29,

preferably at the upper end of the primary cylinder l2, which reservoiris connected to the lower end of the cylinder i2 .by means of apassageway 29, terminating in the port provided by the valve seat 22.. Acheck valve 21 is provided at the lower or outer end of the primarycylinder l2 to permit fluid to be drawn into the cylinder upon movementof the plunger l9 away from this valve.

The upper wall of the primary cylinder i2 is provided with a restrictedport 29, preferably of arcuate outline, through which fluid may escapefrom the primary cylinder l2 upon movement of the piston head l9 ofplunger toward this port. A valve 99 including a valve stem 9| isprovided to regulate the flow through the port 29, the valve beingprovided with 9. preferably arcuate port 92. Valve 99 is ordinarilyturned to partially align its port 92 with port 29, as shown in Figure3, so that the flow through the latter port will be restricted by port92.- In order to permit adjustment of the port 92 of the valve 99 withrespect to the port 29, a collar 99 is provided upon the upper end ofthe casing ii, which collar is keyed to the valve stem 9|, as shown at94. The collar 99 may be held locked in adjusted position with respectto the casing i I by means 01' set screws 95 threaded in the valvefltting 99 and extending through arcuate slots in the collar 99.

A coil spring 91 is positioned between the inner surface of the valvefitting 99 and the upper surface of the valve 99 and, under normalpressures, holds the latter downwardly against the wall 99 between thereservoir 25 and the primary cylinder l2. However, should the pistonhead l9 of plunger l9' move upwardly too suddenly or with too great apressure, the spring 91 will permit the valve 99 to open, therebyenabling fluid to flow from the primary cylinder l2 through the entirearea of the port 29.

The keyed connection between the collar 99 and valve stem 9i will permitthe valve to raise and to again descend without any change in'thecircumferential positioning of the valve with respect to the port 29.

A check valve 49 is also provided at the upper end of the primarycylinder i2 to permit inward flow of fluid from the reservoir 29 to thecylinder upon the downward movement of the plunger l9.

In the operation of the shock absorber of my invention, as applied to avehicle, assuming that the plunger i9 is operatively connected to thebody of the vehicle and that the casing ii is operatively connected tothe running gear or axle, a road shock will cause the plunger I9 and theeasing i I to move toward each other, with the result that the pistonhead i9 will move downwardly in the primary cylinder l2. The oil,glycerine or similar substantially non-compressible fluid within thecylinder'l2 will exert pressure upon the -valve l9 to move the latterdownwardly to open the passageway 19 to the secondary cylinder ll.

The fluid flowing through the passageway l9 will act upon the uppersurface of the piston I! in the secondary cylinder l4, forcing thelatter piston downwardly against the action of the spring i9 and the airor compressible fluid within the cylinder ll. The piston it will therebycushion the movement of the plunger I9. It will be observed that meanswill be provided to always hold the upper face of the piston 19 spacedfrom the upper end of the cylinder ll, so that its entire upper surfacewill be exposed to the oil flowing from passage l9. During the movementof the plunger l9 described above, oil will be permitted 9 to flow intothe upper end of the primary cylinder i2 through the check valve 99.

Upon rebound movement of the parts of the shock absorber, the upwardmovement of the plunger l9 will cause the oil to be expelled, from theupper end of the cylinder l2 through the port 29 in the cylinder wall 99and thence through the port 92 in the valve 99. Should the rebound shockbe severe, the greater pressure thereby exerted-upon the portion of thevalve 99 exposed at the port 29 will cause valve 99 to be lifted againstthe action of the spring 91, permitting oil to flow more rapidly fromthe cylinder i2 and thereby preventing the plunger ill from being heldrelatively stationary with respect to the casing i I. 20

The check valve 49 will, of course, be held closed upon upwardmovement'oi' the plunger II, but the check valve 21 will open to permitoil to flow into the lower end of primary cylinder i2 from thepassageway 29. The valve l9 will close immediately the plunger l9 beginsto rise and the spring I 9 in the secondary cylinder II will also raisethe piston I! to cause the oil to be expelled from the cylinder itthrough the passageway l9, past the valve seat 22 and into thepassageway 29 connected to the reservoir.

It is to be understood that the invention is not limited to the detailsof construction shown in the drawing and described in the speciflcationand that the example of the use of the device which has been given doesnot include all of the uses of which it is capable; also, that thephraseology employed in the specification is for the purpose ofdescription and not of limitation.

I claim:

1. A shock absorber comprising a casing member, a plunger member, saidmembers being adapted to be operatively connected to relatively movableelements, a primary cylinder in which said plunger member is movable, asecondary cylinder having a fluid cushioned piston therein, a reservoir,a valve to permit fluid flow from said primary cylinder to saidsecondary cylinder in one direction of movement of said plunger memberand to permit flow from said secondary cylinder to said reservoir duringmovement of said plunger member in the opposite directionQsaid primarycylinder having a port at one end there- 01' to permit fluid flow tosaid reservoir during the last-mentioned movement of said plungermember.

2. A'shock absorber comprising a casing mem- .be!', a plunger member,said members being but flow of fluid to said reservoir from the portionof said first-named cylinder distant from said connection.

3. A shock absorber comprising a casing mem- '75 inder of said casingmember, said members being adapted to be operatlvely connected torelatively movable elements, a second cylinder, a

piston in said second cylinder adapted to move in response to movementsof said plunger memloer in one direction, said cylinders and saidreservoir losing connected by a port, a valve for said port nolepted toalternately permit flow from eniol first cylinder to said secondcylinder and from. second cylinder to said reservoir but to innintainsaid first cylinder constantly closed ironi'cniol reservoir, and meansto permit flow from. first cylinder to said reservoir.

A. check elccorber comprising a fluid coneasing member, a plungermember, said bers using adapted to be operatively conelite-ll torelatively movable elements, a cylinin mini casing member in which saidplunger miracle movable, n reservoir communicating l cylinder through afluid port, a valve controlling the flow oi fluid through said a pistonchamber associated with the casling ineniher, a passage communicatingthe piston clinmher with the cylinder and the reservoir, end vnlve meansin said passage for selectively ecntrelling communication of the pistonchamber with the cylinder and the reservoir.

Ea. shock absorber comprising a fluid contcinlng casing member, aplunger member, said embers being oriented to be operatively contec'l torelatively movable elements, a cylinin cold (legging member in whichsaid plunger m leer movable, a reservoir arranged to comwlth thecylinder on one side oi the piston chamber arranged to communalthecylinder on the opposite slde'oi the communicating the piston chamberwith the cylinder and the reservoir, and a single valve in said passagefor selectively controlling communication of the piston chamber with thecylinder and the reservoir.

6. A shock absorber comprising a fluid containing cylinder member, aplunger member movable within said cylinder member, said members beingadapted to be operatively connected to relatively movable elements, anauxiliary cylinder, a piston in said auxiliary cylinder adaptedto bemoved in response to movement of said plunger member, a reservoirarranged to communicate with the cylinder member and the auxiliarycylinder, a single valve for selectively controlling communication 01'the auxiliary cylinder with the cylinder member and the reservoir, andautomatic valve means associated with the auxiliary cylinder to permitatmospheric pressure to flow to said auxiliary cylinder and prevent theforms. tion 01' a vacuum therein.

'7. A shock absorber comprising a liquid containing casing member, aplunger member movable within said casing member, and dividing the sameinto an upper and lower chamber, said members being adapted to beoperatively connected to' relatively movable elements, a piston in saidcasing member positioned below the plunger member and adapted to move inresponse to movement oi'said plunger member in one direction, means forestablishing liquid communication between said chambers, and pressureresponsive means located above the plunger member to permit apredetermined flow of fluid from the path oi movement 01' said plungermember when the latter is moved away from the piston and adapted topermit a greater flow under nbnormal conditions.

JOHN W. I'LYNN.

